Liquid pressure transfer method, transfer film therefor and product decorated thereby

ABSTRACT

A workpiece to which a transfer pattern is to be applied is formed to have a rod-like element curved into a loop-like shape to form an apparent geometric plane. A transfer film used in the liquid pressure transfer is formed on a required portion thereof, and the transfer pattern for decoration is formed to have a configuration corresponding to that of the apparent plane. The workpiece is handled so as to downwardly approach the transfer film from a position corresponding to the transfer pattern, and is then immersed in the transfer liquid. Consequently, the transfer film bonds to the rod-like element of the workpiece so as to circumferentially surround the rod-like element continuously from a bottom of the rod-like element to a top thereof on the basis of a diametric section of the rod-like element. Thus, the transfer pattern is transferred to at least the rod-like element of the workpiece.

[0001] This application is a Divisional application of Ser. No.09/514,337, filed Feb. 28 2000, now allowed.

BACKGROUND OF THE INVENTION

[0002] This invention relates to a liquid pressure transfer method, andmore particularly to a liquid pressure transfer printing method forapplying a pattern for decoration specifically intended for a workpiecesuch as a steering wheel for an automobile or the like which includes arod-like element curved to form a predetermined apparent plane to theworkpiece.

[0003] For example, a steering wheel for an automobile has a core madeof a metal material so as to exhibit strength of at least apredetermined level. The core is provided therearound with a gripsurface, which is formed of a material such as a plastic material, awooden material, a leather material or the like, which is selecteddepending on requirements such as operability of the steering wheel,decorative characteristics thereof and the like. For example, a steeringwheel provided thereon with a wooden surface is evaluated to be ahigh-quality article, because it exhibits both satisfactory operabilityand decorative characteristics and requires considerable labor and timefor manufacturing. However, a recent tendency to reconsider theeasygoing use of a natural material in view of protecting the naturalenvironment, and a demand for reduction of a manufacturing cost had ledto development of liquid pressure transfer printing techniques. Thesetechniques involve transfer printing on a plastic steering wheelmaterial in place of a wooden steering wheel material to apply awoodgrain pattern for decoration thereto.

[0004] Application of a decorative pattern to a workpiece by liquidpressure transfer permits formation of a natural pattern which exhibitssatisfactory conformability to a configuration of the workpiece,resulting in the technique being extensively practiced on a variety ofworkpieces. However, application of such liquid pressure transfer to,for example, a steering wheel encounters some important problems. Aconventional steering wheel made of a wooden material is manufactured bysubjecting two wooden rod-like materials which are semicircular insection to a treatment by moistening and heating to bend them into anannular shape, and then bonding them to each other while interposing acore therebetween. Thus, of course the wooden materials are each soarranged that a straight grain extends in a circumferential direction ofthe steering wheel. Such arrangement of the straight grain permits auser to have a sense of security or a sense of reliability.

[0005] Unfortunately, in application of a decorative pattern to aworkpiece by liquid pressure transfer, a transfer film having a transferpattern formed thereon is supported on a surface of a transfer liquidwhile being floated thereon, so that exact positioning or registrationbetween the transfer film and the workpiece is relatively difficult.Thus, in the prior art, a continuously-formed decorative pattern such asa woodgrain pattern, a natural stone pattern, or a carbon fiber patternis arranged all over the transfer film so as to allow misregistrationwhich occurs between the transfer film and the workpiece. Consequently,a decorative pattern similar to a natural material is providedirrespective of a portion of the pattern transferred to the workpiece.Nevertheless, development of techniques of reproducing a transferpattern specifically intended for a desired product such as, forexample, techniques of arranging a straight grain pattern in acircumferential direction of a steering wheel, are still demanded.

SUMMARY OF THE INVENTION

[0006] The present invention has been made in view of the foregoingdisadvantage of the prior art.

[0007] Accordingly, it is an object of the present invention to providea liquid pressure transfer method which is capable of applying adecorative pattern specifically intended for a specific or desiredworkpiece such as a steering wheel or the like to the workpiece.

[0008] It is another object of the present invention to provide atransfer film which is capable of facilitating application of adecorative pattern specifically intended for a workpiece such as asteering wheel or the like to the workpiece.

[0009] It is a further object of the present invention to provide aproduct decorated according to the liquid pressure transfer methoddescribed above.

[0010] In accordance with one aspect of the present a liquid pressuretransfer method for carrying out liquid pressure transfer printing on aworkpiece such as a steering wheel is provided. The liquid pressuretransfer method includes the step of supporting a transfer film on asurface of a transfer liquid while floating it thereon. The transferfilm has a transfer pattern for decoration printed thereon. The liquidpressure transfer method also includes the step of downwardly immersinga workpiece in the transfer liquid to transfer the transfer pattern to asurface of the workpiece, to thereby decorate the workpiece. Theworkpiece includes a rod-like element curved into a loop-like shape,resulting in it being formed in an apparent geometric plane whichpermits the workpiece to be recognized as a whole. The transfer patternis formed to have a configuration corresponding to a configuration ofthe apparent plane of the workpiece, and is arranged on a requiredposition of the transfer film. The workpiece is handled so as toapproach the transfer film from a position above the transfer patterncorresponding to the transfer pattern and is then immersed in thetransfer liquid. Therefore, the transfer film bonds to the rod-likeelement of the workpiece in a manner to circumferentially surround therod-like element continuously from a bottom of the rod-like element to atop thereof on the basis of a diametric section of the rod-like element,resulting in the transfer pattern being transferred to at least therod-like element of the workpiece.

[0011] The liquid pressure transfer method thus constructed permits theworkpiece, such as a steering wheel or the like which includes therod-like element curved to form a predetermined apparent plane, to bereadily and positively decorated with a transfer pattern specificallyintended for the workpiece.

[0012] In a preferred embodiment of the present invention, an approachattitude angle defined between the apparent plane of the workpiece andthe surface of the transfer liquid is set to be within a range of ±15°.This permits the optimum approach attitude angle to be set depending ona type of the transfer pattern, as well as a size of the workpiece, aconfiguration thereof and the like.

[0013] In a preferred embodiment of the present invention, the workpieceis immersed in the transfer liquid in a substantially verticaldirection. Such vertical lowering of the workpiece to the surface of thetransfer liquid facilitates transfer of the transfer pattern to theworkpiece.

[0014] In a preferred embodiment of the present invention, the transferfilm is provided thereon with reference position marks for enablingrelative registration between the transfer pattern and the workpiece.This permits positioning or registration between the transfer patternand the workpiece to be readily attained while preventingmisregistration of the transfer film.

[0015] In accordance with another aspect of the present invention, atransfer film is provided. The transfer film includes a film body whichhas a transfer operation surface defined thereon. The transfer operationsurface has a predetermined transfer pattern previously printed thereonin transfer ink. When transfer is to be carried out, the transferoperation surface is coated thereon with an activator to permit aportion of the transfer operation surface to which the transfer ink isapplied to exhibit stickiness. The transfer film is supported on asurface of a transfer liquid while being floated thereon. The transferpattern is transferred to a surface of a workpiece by a liquid pressureproduced when the workpiece is downwardly immersed in the transferliquid. The transfer film is applied to the workpiece including arod-like element curved into a loop-like shape, resulting in theworkpiece being formed with an apparent plane which permits theworkpiece to be recognized as a whole. The transfer pattern is formed tohave a configuration corresponding to a configuration of the apparentplane of the workpiece and arranged on a required position of thetransfer film. The transfer film thus constructed permits the transferpattern specifically intended for the workpiece to be readily applied tothe workpiece, to thereby facilitate decoration of the workpiece.

[0016] In a preferred embodiment of the present invention, the workpieceis a steering wheel. The transfer pattern is formed to have asubstantially annular shape in correspondence to the apparent plane ofthe steering wheel. Thus, in the present invention, although distortionof the pattern is varied depending on a position on a circumference of adiametric section of the rod-like element of the workpiece, the patterndistortion in a circumferential direction of the whole steering wheel issubstantially the same irrespective of a position on the rod-likeelement in the circumferential direction thereof Thus, the transferprinting may be carried out while rendering the pattern distortioninconspicuous.

[0017] In a preferred embodiment of the present invention, the transferpattern is formed to have a substantially annular shape by taking inpattern data having a plane rectangular shape and then converting thepattern data into pattern data having a round shape. This permits thetransfer pattern specifically intended for the workpiece to be moreexactly reproduced on the workpiece.

[0018] In accordance with a further aspect of the present invention,there is provided a decorated product to which a predetermineddecorative pattern is applied by subjecting a workpiece such as asteering wheel or the like including a rod-like element to liquidpressure transfer printing in which the workpiece is downwardly immersedin a transfer liquid which supports a transfer film having a transferpattern for decoration printed on a surface thereof while floating it onthe transfer liquid. Therefore, the transfer pattern is applied to atleast the rod-like element of the workpiece. The workpiece is operatedso as to permit the transfer pattern to be printed on the rod-likeelement of the workpiece in a manner to circumferentially surround therod-like element continuously from a bottom of the rod-like element to atop thereof on the basis of a diametric section of the rod-like element.Consequently, transfer of the transfer pattern to the workpiece iscarried out according to the above-described liquid pressure transfermethod while ensuring exact reproducibility of the transfer pattern.

[0019] Such construction permits the transfer pattern to be more exactlyreproduced on a variety of workpieces of a closed loop shape or an openloop shape including, for example, a hula hoop, rings in gymnastic, atowel ring, a chair back, a handrail and the like in addition to thesteering wheel while minimizing distortion of the transfer pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] These and other objects and many of the attendant advantages ofthe present invention will be readily appreciated as the same becomesbetter understood by reference to the following detailed descriptionwhen considered in connection with the accompanying drawings; wherein:

[0021]FIG. 1A is a schematic side elevation view showing an apparatuswhich is adapted to practice a liquid pressure transfer method accordingto the present invention, wherein an immersion angle is set to be 0° byway of example;

[0022]FIG. 1B is an enlarged partial cross sectional view of part 1B ofFIG. 1A;

[0023]FIG. 2 is a schematic side elevation view showing the apparatuswhich is adapted to practice a liquid pressure transfer method accordingto the present invention, wherein the immersion angle is set to be 20°;

[0024]FIGS. 3A to 3C are plan views showing a transfer pattern formed ona transfer film;

[0025]FIG. 4A is a perspective view showing a steering wheel which is anexample of a decorated product according to the present invention;

[0026]FIG. 4B is a sectional view taken along line 4B-4B of FIG. 4A;

[0027]FIGS. 5A to 5C are schematic views showing steps of liquidpressure transfer by stages, respectively;

[0028]FIG. 6 is a schematic side elevation view showing a unit forcontinuously feeding a transfer film to a transfer bath, in which atransfer liquid flows; and

[0029]FIG. 7 is a schematic view showing a procedure for convertingpattern data of a rectangular shape into pattern data of an annularshape.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Now, the present invention will be described in detail withreference to the accompanying drawings. The following description willbe first made on a workpiece to be decorated according to the presentinvention. Then, a liquid pressure transfer printing apparatus forcarrying out liquid pressure transfer printing on such a workpiece isschematically described. Subsequently, a liquid pressure transferprinting method according to the present invention will be describedtogether with a manner of operation of the liquid pressure transferprinting apparatus.

[0031] A workpiece designated by reference character W in FIGS. 1A, 1Band 2 includes a rod-like element formed to be curved to define apredetermined apparent geometric plane R which permits the workpiece tobe recognized as a whole. Thus, the workpieces to which the presentinvention is applicable may include, for example, a steering wheelmounted on a vehicle or the like, as well as products of an annularshape, a substantially O-shape or the like which form a closed loop suchas a hula hoop, rings in gymnastics, a towel ring and the like, andproducts of a substantially U-shape which form an open loop such as achair back and the like. Further, the workpieces may include productssuch as a handrail for stairs and the like wherein two loop-like membersare connected together through one or two straight members.

[0032] The apparent plane R is defined as a plane literally when thepresent invention is applied to a steering wheel as the workpiece W.However, it is not necessarily defined as a plane when the presentinvention is applied to a chair back as the workpiece W. In that case,the apparent plane R may be often defined so as to somewhat have acurvature.

[0033] Also, the illustrated embodiment will be described essentially inconnection with the case that the present invention is applied to asteering wheel as the workpiece W. Thus, when it is necessary todistinguish a steering wheel before the liquid pressure transferprinting of the present invention from a steering wheel after thetransfer printing, a steering wheel which has been subjected to theliquid pressure transfer printing is designated by reference character1, and a steering wheel before the printing is designated by 1A.

[0034] Now, the steering wheel 1 which has been subjected to the liquidpressure transfer printing will be described with reference to FIGS. 4Aand 4B by way of example. The steering wheel 1 includes a boss section 2acting as a center of rotational movement of the steering wheel 1, spokesections 3 arranged so as to radially extend from the boss section 2,and a rim section 4 connected to a distal end of each of the spokesections 3 and formed to have a substantially annular shape. The rimsection 4, as shown in FIG. 4A, includes a long rim portion 41 of anelongated arcuate shape (positioned on an upper side in FIG. 4A), ashort rim portion 42 of a short arcuate shape (positioned on a lowerside in FIG. 4A), and two grip portions 43 for connecting the long rimportion 41 and short rim portion 42 to each other therethrough(positioned on both lateral sides in FIG. 4A). The long rim portion 41and short rim portion 42 have a transfer pattern P specifically intendedfor the workpiece W such as a woodgrain pattern, a straight grainpattern or the like, applied thereto and is formed thereon with atopcoat.

[0035] The grip portions 43 are each connected to the spoke sections 3which extend from the boss section 2. It is considered that the spokesections 3 cause force which is different from that acting on the otherportions, such as the long rim portion 41 and short rim portion 42, toact on the transfer film F during the transfer. This prevents liquidpressure transfer printing like that carried out on the other portionsto be attained on the grip portions 43. Thus, for example, techniques ofwrapping a suitable material such as leather or the like around the gripportions 43 may be employed after transfer printing, to thereby hideprinting applied to the grip portions 43 or to apply a specialdecoration effect or a grip feel to the grip portions. However, unlessprinting applied to the grip portions 43 adversely affects an appearanceof the product or causes any problem, such techniques may be eliminated.Also, when it is not desired to apply liquid pressure transfer printingto the grip portions 43, they may be covered with any suitable maskingmaterial in advance.

[0036] In printing applied to the rim section 4, the transfer pattern Pspecifically intended for the workpiece W or steering wheel 1A istransferred to the rim section 4, wherein the illustrated embodimentpermits pattern distortion to be inconspicuous as compared with theprior art. This is due to the fact that the transfer pattern P issubstantially formed to have an annular shape corresponding to aconfiguration of the steering wheel 1A. More particularly, in adiametric section of the rod-like element of the steering wheel 1A or asection of the rod-like element of the steering wheel taken in adiametric direction of the rod-like element, distortion of the transferpattern P is varied depending on a position on a circumference of thediametric section of the rod-like element. However, the patterndistortion in a circumferential direction of the whole steering wheel 1Ais substantially the same irrespective of positions thereof. Thispermits the pattern distortion on the whole steering wheel 1A to beinconspicuous as a whole. The transfer pattern P is so arranged that ajoint line Pa of the transfer pattern P is positioned on a rear surfaceof the steering wheel 1 which is substantially out of sight of a driverwhen the steering wheel is mounted in a vehicle.

[0037] Now, a liquid pressure transfer printing apparatus 10 will bedescribed with reference to FIG. 1A by way of example. The liquidpressure transfer printing apparatus 10 includes a transfer bath 11, atransfer film storage unit (not shown) and a workpiece holding unit 13.

[0038] The transfer bath 11 has a transfer liquid L stored therein, anda transfer film F is supported on a surface of the transfer liquid Lwhile being floated thereon. In the illustrated embodiment, the transferfilms formed in individual sheets are fed to the transfer bath 11 one byone by hand so as to be floated on the transfer liquid L, so that thetransfer liquid L is always kept stationary.

[0039] The transfer film storage unit is constructed so as to permit thetransfer films F to be taken out thereof one by one.

[0040] The transfer film F may be formed to have a rectangularconfiguration as shown in each of FIGS. 3A to 3C by way of example. Thetransfer film F includes a film body which has a transfer operationsurface defined thereon. The transfer operation surface has the transferpattern P for decoration formed only on a required position thereofcorresponding to a configuration of the apparent plane R of theworkpiece W. In the illustrated embodiment, the transfer pattern P isformed to have a substantially annular shape corresponding to theconfiguration of the rim section 4 of the steering wheel 1. Also, thetransfer film F is suitably provided thereon with reference positionmarks M which permit relative positioning or registration between thetransfer pattern P and the workpiece W to be carried out therethrough.In the illustrated embodiment, the reference position marks M include across-like mark arranged on a substantially central position of thetransfer pattern, four radial marks arranged at substantially equalangular intervals on an outside of the transfer pattern P, and the likeby way of example, as shown in each of FIGS. 3A to 3C.

[0041] A transfer film F shown in FIG. 3A is adapted to be directed todecoration of the workpiece W carried out when the workpiece W isvertically lowered to the surface of the transfer liquid L whilemaintaining an approach attitude angle α of the workpiece W at 0°. Thetransfer film F of FIG. 3A has a transfer pattern P of a substantiallyconcentric shape formed thereon with high accuracy. A transfer film Fshown in FIG. 3B is directed to the decoration when the workpiece W isvertically lowered to the liquid surface while maintaining the approachattitude angle α at suitable degrees. Thus, the transfer film F of FIG.3B corresponds to that shown in FIG. 1. The transfer film F of FIG. 3Bhas a transfer pattern P which is formed to have a substantially annularshape provided thereon, wherein a major axis Ac and a minor axis Atthereof extend in a vertical direction and a horizontal direction ofFIG. 3B, respectively. A transfer film F shown in FIG. 3C is directed todecoration of the workpiece W when it is obliquely lowered to the liquidsurface while maintaining an approach attitude angle α thereof atsuitable degrees. The transfer film F corresponds to that describedhereinafter with reference to FIG. 2. Thus, the transfer film F of FIG.3C has a transfer pattern P formed to have a substantially annularshape, wherein a minor axis At and a major axis Ac thereof extend in avertical direction and a horizontal direction of FIG. 3C, respectively.The term “substantially annular shape” referred to herein indicates suchconfigurations as shown in FIGS. 3A to 3C. Thus, the substantiallyannular shapes include a substantially complete annular shape as shownin FIG. 3A, as well as somewhat deformed annular shapes as shown inFIGS. 3B and 3C. Therefore, as seen in the attached drawings, thetransfer pattern is printed only on an area of the transfer film F thathas a shape corresponding to a surface shape of the workpiece W to becovered by the transfer pattern. Also, the transfer film F shown in eachof FIGS. 3A to 3C has only one transfer pattern P printed thereon.Alternatively, the transfer film may have a plurality of transferpatterns P printed thereon.

[0042] Further, forming the transfer pattern P into a substantiallyannular shape for the purpose of transferring, for example, a woodgrainpattern to the workpiece is carried out by subjecting an image of awoodgrain actually photographed to image processing by means of acomputer or preparing a picture of a woodgrain directly by means of acomputer, to thereby convert a pattern to be transferred into patterndata of a plane rectangular shape. Then, the plane rectangular patterndata thus converted are converted into pattern data of a round orring-like shape on the computer, resulting in the transfer pattern Pbeing formed to have a substantially annular shape. Thus, it will benoted that when the plane rectangular pattern before the conversion isrepresented in a coordinate system containing X and Y coordinate axeswhich are perpendicular to each other as shown in FIG. 7, the conversionpermits the X axis to be converted into a circumferential direction andthe Y axis to be converted into a radial direction, resulting in thetransfer pattern P of a substantially annular shape being provided. Ofcourse, the operation of joining opposite ends of the plane rectangularshape to each other is carried out with suitable image processing forrendering the joint inconspicuous, such as connecting woodgrain lines toeach other.

[0043] The above description has been made for conversion of thetransfer pattern into a round shape carried out immediately after takingin the transfer pattern as the pattern data of a plane rectangularshape. However, for example, it is considered that the pattern dataphotographed may be too small to be developed in the circumferentialdirection. More particularly, the pattern data of a plane rectangularshape indicated by solid lines shown in FIG. 7 have a dimension in the Xaxis direction sufficient to be converted into the circumferentialdirection. However, the pattern data having such a large size is notnecessarily photographed. In order to solve the problem, an approach maybe employed which is constructed so as to introduce pattern data of asmall size readily photographed into an image processing unit and torepeat the pattern data to prepare plane rectangular pattern data of adesired large size.

[0044] Another approach which may be employed is to introduce patterndata of a small size into an image processing unit and thenindependently multiply a longitudinal dimension of the pattern data anda lateral dimension thereof on a screen of the unit to obtain planerectangular pattern data of a desired size. Repeating of suchsmall-sized pattern data for formation of such plane rectangular patterndata of a desired size may be carried out on the same pattern.Alternatively, patterns different from each other may be connected toeach other. The operation of multiplying the longitudinal dimension andlateral dimension independently from each other is effective to not onlyconvert the pattern data into a desired size but also, for example, toset the density of woodgrain lines at a suitable level.

[0045] The workpiece holding unit 13 functions to immerse the steeringwheel 1A into the transfer liquid L while holding it. In the immersion,an approach attitude angle α defined between the apparent plane R of theworkpiece W and the surface of the transfer liquid L is set to be withina range of ±15° based on a horizontal direction. The symbols “+” and “−”referred to herein do not have any specific definition. They merely meanthat one rotational direction from a certain reference positionindicates “+” and the other rotational direction indicates “−”. Also, inthe illustrated embodiment, the workpiece W is immersed in the transferliquid L in a vertical direction as shown in FIG. 1A. However, adirection of immersion of the workpiece W may be suitably varied. In thepresent invention, the direction of immersion is indicated by an angle βbetween the direction of immersion and a line normal to the surface ofthe transfer liquid, which angle is defined to be an immersion angleherein. When the workpiece is immersed in the normal direction as shownin FIG. 1A, the immersion angle is defined to be 0°, that is, theworkpiece is vertically lowered. The approach attitude angle at andimmersion angle β are each suitably set depending on various factorssuch as a size of the transfer pattern P, a size of the steering wheel1A, a thickness of the rod-like element, and the like. However, theangles set are not necessarily kept constant during transfer of thetransfer pattern to the workpiece. For example, when the apparent planeR of the workpiece W somewhat has a curvature, the angle may be suitablyvaried after start of the immersion. For example, in the immersion shownin FIG. 2, the approach attitude angle α and immersion angle β are setto be 10° and 20°, respectively.

[0046] Now, liquid pressure transfer printing on the workpiece such as asteering wheel or the like will be described in relation to operation ofthe liquid pressure transfer printing apparatus 10 thus constructed.

[0047] (1) Feeding of the Transfer Film:

[0048] First, the transfer film F is fed onto the transfer liquid L inthe transfer bath 11 while an activator is coated on a surface of thetransfer film F to which a transfer ink is applied. The activator may bemade by, for example, mixing a resin material, a pigment, a solvent, aplasticizer and the like with each other at suitable ratios.Alternatively, a solvent such as a thinner or the like may be merelyused as the activator. Thus, the term “activators” referred to hereininclude a thinner and the like. The transfer film F thus coated thereonwith the activator absorbs water, to thereby be softened and swollen,resulting in it somewhat extending in all directions. Coating of theactivator on the transfer film F is necessary because the transfer filmF is normally stored while the applied transfer ink is kept dry. Thus,the coating permits the ink coated surface of the transfer film F to beprovided with stickiness, so that the ink on the transfer film F may betransferred. Also, coating of the activator on the transfer film F maybe carried out after feeding of the transfer film F onto the transferliquid L as well. Thus, the terms “the activator is coated on thetransfer film to provide the ink coated surface of the transfer filmwith stickiness and permit the transfer film to be floated on thetransfer liquid” referred to herein or an expression similar theretodoes not limit the steps to any specific order. Thus, in the presentinvention, coating of the activator may be carried out either afterfloating of the transfer film F on the transfer liquid or prior thereto.

[0049] (2) Feeding of Steering Wheel:

[0050] The workpiece W or steering wheel 1A is set so that a frontsurface thereof (defined by the time when it is mounted in a vehicle) iskept facing the transfer film F. This permits the joint line Pa of thetransfer film F to be positioned on a side of a rear surface of thesteering wheel which is substantially out of sight of a driver. Then,the steering wheel 1A is immersed in the transfer liquid L while beingsuitably maintained at an approach attitude angle α and an immersionangle β by the workpiece holding unit 13. The approach attitude angle αand immersion angle β are not necessarily kept constant during thetransfer. The angles α and β may be suitably varied depending on theapparent plane R formed or the like after the start of the immersion aswell. Also, the transfer film F, as described above, may be providedthereon with the reference position marks M for relative registrationbetween the transfer pattern P and the workpiece W. Such arrangement ofthe reference position marks M permits a position at which immersion ofthe steering wheel 1A is started to be readily determined.

[0051] (3) Transfer:

[0052] When the steering wheel 1A is immersed in the transfer liquid L,the transfer film F is continuously bonded to the steering wheel 1A, sothat the transfer pattern P may be transferred to the steering wheel 1Awhile keeping distortion of the pattern P inconspicuous. The transfermay be carried out as shown in FIGS. 5A to 5C by way of example. Moreparticularly, the transfer film F circumferentially surrounds therod-like element continuously from a bottom of the rod-like element to atop thereof on the basis of a diametric section of the rod-like elementwith progress of immersion of the steering wheel 1A in the transferliquid L, so that the transfer film F ultimately forms the joint line Pawhen it reaches the rear surface side of the steering wheel 1A. Then,the joint line Pa is formed on a whole circumference of the rear surfaceof the steering wheel 1A, resulting in the transfer being substantiallycompleted.

[0053] Now, distortion of the transfer pattern P on the steering wheel1A will be described. First, it is supposed that on a circumference ofthe diametric section of the rod-like element of the steering wheel 1A,a lowermost point at which the transfer is first initiated, an uppermostpoint at which the joint line Pa of the transfer pattern P is formed, aninnermost peripheral point positioned between the lowermost point andthe uppermost point, and an outermost peripheral point positionedtherebetween are designated by reference characters P0, P1, P2 and P3 inFIG. 1B, respectively. In this instance, in a region in which thetransfer is carried out from the lowermost point P0 through theinnermost peripheral point P2 to the uppermost point P1, a radius of therod-like element projected on a horizontal plane is gradually decreasedfrom the lowermost point P0 to the innermost peripheral point P2 andgradually increased from the innermost peripheral point P2 to theuppermost point P1. Consequently, in a region where the transfer iscarried out from the lowermost point P0 through the outermost peripheralpoint P3 to the uppermost point P1, the radius of the rod-like elementprojected on a horizontal plane is gradually increased from thelowermost point P0 to the outermost peripheral point P3 and graduallydecreased from the outermost peripheral point P3 to the uppermost pointP1.

[0054] In order to eliminate distortion of the transfer pattern over thewhole circumference or periphery of the diametric section of therod-like element of the steering wheel 1A, the transfer pattern P wouldbe preferably formed so as to permit such a radius of the rod-likeelement projected on a horizontal plane to be substantially exactlyreproduced. However, this is highly difficult. Therefore, the actualtransfer pattern P to be printed is formed to have a substantiallyannular shape so that the radius projected on a horizontal plane isincreased in one direction toward an outside of the transfer pattern.This of course causes the transfer pattern to be subject to distortion,so that a degree of pattern distortion on the circumference or peripheryof the diametric section of the rod-like element is of course varieddepending on a position on the circumference of the section. However,the transfer film F is softened and swollen due to immersion thereof inthe transfer liquid L, resulting in substantially extending in alldirections, so that the lowermost point P0, uppermost point P1,innermost peripheral point P2 and outermost peripheral point P3 aresubstantially identical in pattern distortion in a peripheral orcircumferential direction of the whole rod-like element with each other.This permits the pattern distortion on the whole steering wheel 1A to beinconspicuous.

[0055] (4) Removal of Film and Drying:

[0056] The steering wheel 1A which has been thus subjected to the liquidpressure transfer printing has a residue of the transfer film F whichhas not been dissolved in the transfer liquid L adhered thereto. Thus,in order to fully remove the residue, the steering wheel 1A is subjectedto washing by showering or the like, followed by drying.

[0057] (5) Topcoat

[0058] The steering wheel 1A having the transfer pattern thus printedthereon provides the decorated product of the present invention.However, when it is desired that a portion of the steering wheel whichhas been subjected to the transfer printing exhibit increased gloss anddepth of a color, a transparent topcoat is formed thereon by spraying orthe like. The topcoat thus formed may be subjected to polishing bybuffing or the like.

[0059] In the illustrated embodiment, the transfer films F formed inindividual sheets are fed one by one by hand to the transfer bath 11 inwhich the transfer liquid L is kept stationary so that they may befloated on the transfer liquid L. Alternatively, the present inventionmay be constructed in such a manner that a transfer film F iscontinuously fed to the transfer bath 11 in which the transfer liquid Lis kept flowing. In this instance, the steering wheel 1A may bevertically lowered to the transfer bath 11. Alternatively, the steeringwheel may be obliquely lowered to the transfer bath by means of aconveyor of an inverted triangular configuration, an articulated robotor the like. Also, coating of the active agent on the transfer film Fmay be carried out either before feeding of the transfer film F to thetransfer bath 11 or thereafter.

[0060] Referring now to FIG. 6, another embodiment of the presentinvention is illustrated. The embodiment shown in FIG. 6 is constructedso as to continuously feed a transfer film F to a transfer bath 11. Forthis purpose, the transfer bath 11 is provided thereon with acirculation pipe line 14 and a pump 15, so that a transfer liquid L maybe slowly circulated as indicated by an arrow in FIG. 6. Also, thetransfer bath 11 is provided on each of opposite side ends thereof witha guide chain 16. Further, the transfer bath 11 is provided with a fanunit 17, which is positioned on an upstream side of the transfer liquidL. Thus, the transfer liquid L circulated, the guide chains 16, the fanunit 17 and the like cooperate with each other to permit the transferfilm F floatedly supported on a surface of the transfer liquid L to becarried toward a workpiece W or a steering wheel 1A while preventingwaves from forming in the transfer liquid L.

[0061] Also, in the illustrated embodiment, a transfer film feed unit 12is substituted for the transfer film storage unit incorporated in theembodiment described above. The transfer film feed unit 12 includes afilm roll 18 constituted by winding a water-soluble transfer film F in aroll-like manner, a solvent tank 19 having an activator S storedtherein, and feed rollers 20. The transfer film F delivered from thefilm roll 18 is activated by the activator S in the solvent tank 19 andthen continuously fed to the transfer bath 11.

[0062] After the transfer film F fed to the transfer bath 11 which isthus activated is carried to a suitable position, the steering wheel 1Ais immersed in the transfer bath 11 by means of a workpiece holding unit13. Operation of transferring a transfer pattern P from the transferfilm F to the workpiece W in the illustrated embodiment is carried outin substantially the same manner as that in the embodiment describedabove.

[0063] As can be seen from the foregoing, the present invention permitsthe workpiece such as a steering wheel or the like including therod-like element curved to form the apparent plane to be readily andpositively decorated with the transfer pattern specifically intended forthe workpiece.

[0064] Also, the present invention permits the approach attitude angleand/or immersion angle to be optimally set depending on a type of thetransfer pattern, as well as a size of the workpiece, a configurationthereof and the like.

[0065] Further, positioning or registration between the transfer patternof the transfer film floatedly supported on the transfer liquid and theworkpiece is relatively readily attained, to thereby preventmisregistration of the transfer film.

[0066] Moreover, distortion of the pattern is varied depending on aposition on the periphery of the diametric section of the rod-likeelement of the workpiece. However, the pattern distortion issubstantially the same irrespective of a position on the circumferenceof the whole rod-like element. Thus, the transfer printing may becarried out while rendering the pattern distortion inconspicuous.

[0067] While preferred embodiments of the invention have been describedwith reference to the drawings, obvious modifications and variations arepossible in light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims, the inventionmay be practiced other than as specifically described.

What is claimed is:
 1. A transfer film comprising: a film body having a transfer operation surface defined thereon, said transfer operation surface having a predetermined transfer pattern previously printed thereon in transfer ink; wherein, when transfer is not to be carried out, said transfer operation surface is coated thereon with an activator to permit a portion of said transfer operation surface to which said transfer ink is applied to exhibit stickiness and the transfer film is supported on a surface of a transfer liquid while being floated thereon, said transfer pattern being transferred to a surface of a workpiece by a liquid pressure produced when the workpiece is downwardly immersed in the transfer liquid; the transfer film is applied to the workpiece including a rod-like element curved into a loop-like shape, resulting in the workpiece being formed with an apparent plane which permits the workpiece to be recognized as a whole; and said transfer pattern is formed to have a configuration corresponding to a configuration of the apparent plane of the workpiece and arranged on a required position of the transfer film.
 2. A transfer film as defined in claim 1, wherein the workpiece is a steering wheel; and said transfer pattern is formed to have a substantially annular shape in correspondence to the apparent plane of the steering wheel.
 3. A transfer film as defined in claim 2, wherein said transfer pattern is formed to have the substantially annular shape by taking in pattern data of a plane rectangular shape and then converting into pattern data of a round shape.
 4. A transfer film as defined in claim 1, wherein said transfer pattern is formed to have a substantially annular shape by taking in pattern data of a plane rectangular shape and then converting into pattern data of a round shape. 